1. Field of the Invention
The present invention relates to a developing device detachably installed in the main body of an image forming apparatus, a process cartridge comprising this developing device, a device unit, and the image forming apparatus, and particularly relates to a developing device included with shipment in the image forming apparatus main body, with a developer contained therein.
2. Description of the Related Art
In an image forming apparatus, such as a copier, printer, facsimile machine, or complex machine thereof, which uses an electrophotographic system, Japanese Laid-Open Application No. H10-123837 (Page 2, FIG. 6) discloses a conventional technology where a shipment of a developing device is made in a state where the developing device having a developer contained therein beforehand is installed in an image forming apparatus main body, for the purpose of simplifying the packaging system at the time of factory shipment, and of simplifying the unpacking work which is carried out after a user receives the apparatus. Specifically, when a service person or a user himself/herself unpacks an image forming apparatus at a place where he/she happens to be, e.g. installation place, the work of placing a developer in the developing device or in the process cartridge is a burden for the person who unpacks it. In order to solve this problem, a shipment is made in a state where the developer is contained in the developing device beforehand. The act of placing a developer beforehand in the developing device or in the process cartridge when making shipment is appropriately called “presetting” in the present invention.
Further, when packaging the developing device or process cartridge separating from the packaging of the image forming apparatus main body, work efficiency of unpacking by an unpacking worker deteriorates, and also packaging cost or transportation cost increases. In order to solve these problems, the developing device or process cartridge is installed in the image forming apparatus main body, is packaged along with the image forming apparatus main body to make a shipment.
On the other hand, the abovementioned Japanese Laid-Open Application No. H10-123837 discloses a technology in which a surface of a developing roller is covered with a shutter or the like so that, when presetting the developer in the developing device, a developer contained in a developing device does not leak out of an opening which faces a photosensitive drum and from which a part of the developing roller is exposed.
In the conventional image forming apparatus, however, sometimes the developer preset in the developing device is spattered inside the image forming apparatus main body due to a shock or the like applied to the image forming apparatus between when the image forming apparatus was shipped and when it was transported to the user. If the developer contained in the developing device is spattered to the outside of the apparatus, as described above, there occur problems such that the inside of the image forming apparatus main body is stained, impairing functions of various components therein, and the necessary amount of the developer for carrying out the development process cannot be ensured, thus the image quality of an output image is degraded. Therefore, these problems cannot be ignored in providing a highly reliable image forming apparatus.
As disclosed in the abovementioned Japanese Laid-Open Application No. H10-123837, these problems might occur even in an image forming apparatus in which a surface of a developing roller in a developing device is sealed with a shutter or the like. In other words, the developer contained in the developer apparatus might be spattered inside the image forming apparatus main body through a toner conveyance portion of the apparatus main body, the toner conveyance portion being connected to a toner replenishing portion of the developing device. The details are as follows.
Specifically, for the purpose of obtaining a long life developing device, and for some other purposes, a lot of image forming apparatuses comprise a toner conveyance portion for supplying a toner into the developing device. In such an image forming apparatus, the toner is conveyed from the toner conveyance portion of the apparatus main body to a toner replenishing portion of the developing device. The toner replenishing portion of the developing device is communicated with a developer container containing a developer via an opening portion. The toner that is conveyed to the toner replenishing portion is then supplied into the developer container.
Here, the toner replenishing portion of the developing device and the toner conveyance portion of the apparatus main body are configured so as to be freely brought into contact with and separated from each other. Further, the toner replenishing portion and the toner conveyance portion respectively have installed therein shutters that are opened and closed simultaneously with an operation of attaching or detaching the developer apparatus to or from the apparatus main body. When the developer apparatus is attached to the apparatus main body, the toner replenishing portion and toner conveyance portion are connected, and the shutters of both toner replenishing portion and toner conveyance portion are opened so that the toner can be replenished from the toner conveyance portion to the toner replenishing portion. On the other hand, when the developing device is detached from the apparatus main body, the toner replenishing portion and toner conveyance portion are disconnected, and the both shutters are closed so that toner spattering from the toner conveyance portion and developer spattered from the toner replenishing portion are prevented.
In the image forming apparatus with such a configuration, when packaging the image forming apparatus with the developing device installed in the image forming apparatus main body and shipping this package, the toner replenishing portion of the developing device and the toner conveyance portion of the apparatus main body are connected, and the both shutters are opened. In this state therefore, when presetting the developer at the time of shipment, the developer contained in the developer container inside of the developing device flows back from the opening portion to the toner conveyance portion through the toner replenishing portion and is spattered, due to a shock applied to the developing device during transport.